This invention relates to a lever mechanism which may be affixed to a plurality of valve stems by appropriate cable and push rod assemblies for control thereof. In particular, it relates to a single control lever mounted in a bracket assembly which has generally linear travel to control at least two valve stems in a construction machine.
Control of hydraulic circuits in machinery, particularly construction machinery of the mobile type, for example, tracked vehicles, is generally accomplished through lever mechanisms. Operation of these various lever mechanisms is best accomplished with a minimum of change of directions of the lever during positioning in the various operating positions. For example, in a tracked vehicle having a winch mechanism affixed to the rearward end of the vehicle, it is appropriate to provide control of the winch by fore and aft movement of the winch control lever. A simple fore and aft motion is more appropriate for winch control in that the operator may observe the particular load being winched into or away from the winching vehicle without this attention being diverted to visually check the position of the control lever.
A problem with a single control lever in operation of various systems in a construction machine is controlling a plurality of valve stems. Such a plurality of valve stems may become necessary in the complex winch system described in the foregoing paragraph. In such systems, it is appropriate to select the direction of motion of the operated device and secondly, to control the rate at which the operated device is moved. Concurrently, a brake or clutch may be associated with the device which may also be operated by the same single control lever. Thus, a control lever would first select the direction of motion of the controlled device, release the associated brake or engage an operating clutch, and, finally, modulate fluid flow to the motor in accord with the desired rate of speed. To accomplish this in a two-directional lever mechanism requires a particularly unique design, since modulation control might necessarily be required in both directions of motion of the controlled machine.
Although this invention has been described in relation to a two-directional winch, it should be apparent to those skilled in the art that a single control lever to control a plurality of valve stems is not limited to such winch operation. Accordingly, this invention is equally applicable to any multi-valved hydraulic system for which a single control lever is necessary for control.